BANGKOK — By 7pm, Saowalak Unkaew sets up her grilled corn cart at one end of Khaosan Road, something she’s done long before the tourism boom turned it into a bustling hive of commerce about 20 years ago.

BANGKOK — Once hailed for its reliability, the BTS Skytrain’s increasingly frequent system failures led the government to demand answers Monday after commuters were left stranded four hours during this morning’s rush hours.